Pulse

If you have spent days and days fucking around trying to get sound to work with your NVidia 220GT HDMI, you have to use hw:0,7 not hw:0,3 which is the first thing pulse sees, and you need to unmute it in ALSA.

sudo apt-get install alsamixergui

Run alsamixergui and UNMUTE ALL FOUR FUCKING SPDIF CHANNELS. Then, add this to the end of /etc/pulse/default.pa:

load-module module-alsa-sink device=hw:0,7 channels=6 \
  channel_map=front-left,front-right,front-center,lfe,rear-left,rear-right

Alternatively, ditch the piece of shit and use ALSA instead:

sudo apt-get install gstreamer0.10-alsa gnome-alsamixer
sudo apt-get purge pulseaudio gstreamer0.10-pulseaudio